1. Field of the Invention
The present invention relates to an optical lens device assembly which is sealed with a resin and is suitably used for an optical module for communications and more particularly to the optical lens device assembly being suitably used in an assembly made up of microlenses.
2. Description of the Related Art
In an optical module for communications, it is desirable that an optical device making up the optical module is held in a sealed state in order to protect it from the influence of dust or humidity. Therefore, conventionally, a clearance between a laser diode being used as a light emitting element and an optical fiber used as an optical waveguide which receives signal light emitted from the laser diode is sealed with a resin material. In this case, the resin material placed between the optical waveguide and light emitting element has a refractive index the same as that of the optical waveguide, and therefore the optical waveguide can be extended in a pseudo manner so as to reach the light emitting element. As a result, without causing a drop in coupling efficiency between the optical waveguide and light emitting element, the clearance between them can be substantially sealed.
On the other hand, in a module in which an optical device is embedded, the optical lens device does not properly work as originally designed depending on the refractive index of the resin material to be applied. Since the lens design strongly depends on the indices of refraction of the lens material and the surrounding resin, therefore, sealing using such the resin material is not employed. A method is being used in which an optical device to be optically coupled to the optical lens device is housed in a housing for sealing having a window for optical coupling for the optical lens device.
However, when a sealing mechanism using the conventional housing for sealing as described above is used, configurations of the module and its manufacturing processes are made complicated, thus causing an increase in costs.
In view of the above, it is an object of the present invention to provide an optical lens device assembly containing an optical lens device which can be sealed without causing complication of optical module configurations.
According to a first aspect of the present invention, there is provided an optical lens device assembly including an optical lens device serving as a first optical device, a second optical device to be optically coupled to the optical lens device and a resin member having optical transmittance used to fill in space between the first optical device and the second optical device. The resin member is made up of a resin material having a refractive index different from that of the optical lens device and is used to seal a clearance between optical planes, which face each other, of the both optical devices and to mechanically couple the optical lens device to the second optical device.
In the foregoing, a preferable mode is one wherein the first optical device is a microlens.
Also, a preferable mode is one wherein the both optical devices are microlenses.
Also, a preferable mode is one wherein the first optical device is a microlens in which a lens plane is formed on at least one end face of an optical substrate made up of a silicon crystal.
Also, a preferable mode is one wherein the first optical device is made up of silicon crystal and the resin member is made up of silicone resin.
Furthermore, a preferable mode is one wherein the first optical device is designed so that its optical characteristics are acquired based on a refractive index of the resin material.
With the above configurations, by the resin member placed between the optical lens device and the second optical device being optically coupled to the optical lens device, without loss of optical functions of the optical lens device, the clearance between them can be sealed, and therefore a factor of interference, such as a temperature, humidity, dust or a the like, can be removed. Moreover, without use of any other special fixing unit, reliable positioning of the optical lens device and the second optical device is achieved, and therefore a deviation in coupling positions caused by vibration in use or other interference factors does not easily occur and the durability of the optical lens device assembly against the interference factors such as the vibration can be improved accordingly.